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https://www.readbyqxmd.com/read/28221151/-techniques-for-percutaneous-access-during-percutaneous-nephrolithotomy
#1
Daniel Pérez-Fentes
The creation of the access is one of the main steps in percutaneous nephrolithotomy, the most complicated for many urologists and the one that limited most the universalization of the technique. From a purely technical point of view, it includes puncture of the excretory tract and dilatation of the percutaneous tract to end with the introduction of an Amplatz type working sheath. The objective of the puncture is to try to access the excretory system through the renal papilla, minimizing the risk of bleeding...
January 2017: Archivos Españoles de Urología
https://www.readbyqxmd.com/read/28220875/theory-of-topological-insulator-waveguides-polarization-control-and-the-enhancement-of-the-magneto-electric-effect
#2
J A Crosse
Topological insulators subject to a time-reversal-symmetry-breaking perturbation are predicted to display a magneto-electric effect that causes the electric and magnetic induction fields to mix at the material's surface. This effect induces polarization rotations of between ≈1-10 mrad per interface in an incident plane-polarized electromagnetic wave normal to a multilayered structure. Here we show, theoretically and numerically, that by using a waveguide geometry with a topological insulator guide layer and magneto-dielectric cladding it is possible to achieve rotations of ≈100 mrad and generate an elliptical polarization with only a three-layered structure...
February 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28220861/electrically-tunable-metasurface-based-on-mie-type-dielectric-resonators
#3
Zhaoxian Su, Qian Zhao, Kun Song, Xiaopeng Zhao, Jianbo Yin
In this paper, we have designed a metasurface based on electrically tunable Mie-type resonators and theoretically demonstrated its tunable response to electromagnetic waves with varying frequency. The metasurface consists of disk-like ferroelectric resonators arrayed on a metal film and the upper surface of resonators is covered by ion gel film which is transparent for incident electromagnetic wave. Using the metal film and ion gel film as electrodes, the permittivity of the resonators can be adjusted by an external electric field and, as a result, the reflection phase of the resonators can be dynamically adjusted in a relatively wide range...
February 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28220761/electrically-tunable-terahertz-polarization-converter-based-on-overcoupled-metal-isolator-metal-metamaterials-infiltrated-with-liquid-crystals
#4
Borislav Vasić, Dimitrios C Zografopoulos, Goran Isić, Romeo Beccherelli, Radoš Gajić
Large birefringence and its electrical modulation by means of Fréedericksz transition makes nematic liquid crystals (LCs) a promising platform for tunable terahertz (THz) devices. The thickness of standard LC cells is in the order of the wavelength, requiring high driving voltages and allowing only a very slow modulation at THz frequencies. Here, we first present the concept of overcoupled metal-isolator-metal (MIM) cavities that allow for achieving simultaneously both very high phase difference between orthogonal electric field components and large reflectance...
February 21, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28220402/the-specific-absorption-rate-of-tissues-in-rats-exposed-to-electromagnetic-plane-waves-in-the-frequency-range-of-0-05-5%C3%A2-ghz-and-sarwb-in-free-moving-rats
#5
Bingxin Chen, Jiamin Wang, Hongxin Qi, Jie Zhang, Shude Chen, Xianghui Wang
As electromagnetic exposure experiments can only be performed on small animals, usually rats, research on the characteristics of specific absorption rate (SAR) distribution in the rat has received increasing interest. A series of calculations, which simulated the SAR in a male rat anatomical model exposed to electromagnetic plane waves ranging from 0.05 to 5 GHz with different incidence and polarization, were conducted. The whole-body-averaged SAR (SARwb) and the tissue-averaged SAR (SARavg) in 20 major tissues were determined...
February 20, 2017: Australasian Physical & Engineering Sciences in Medicine
https://www.readbyqxmd.com/read/28220060/a-pulsed-electromagnetic-field-protects-against-glutamate-induced-excitotoxicity-by-modulating-the-endocannabinoid-system-in-ht22-cells
#6
Xin Li, Haoxiang Xu, Tao Lei, Yuefan Yang, Da Jing, Shuhui Dai, Peng Luo, Qiaoling Xu
Glutamate-induced excitotoxicity is common in the pathogenesis of many neurological diseases. A pulsed electromagnetic field (PEMF) exerts therapeutic effects on the nervous system, but its specific mechanism associated with excitotoxicity is still unknown. We investigated the role of PEMF exposure in regulating glutamate-induced excitotoxicity through the endocannabinoid (eCB) system. PEMF exposure improved viability of HT22 cells after excitotoxicity and reduced lactate dehydrogenase release and cell death...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28220008/multipolar-interference-effects-in-nanophotonics
#7
REVIEW
Wei Liu, Yuri S Kivshar
Scattering of electromagnetic waves by an arbitrary nanoscale object can be characterized by a multipole decomposition of the electromagnetic field that allows one to describe the scattering intensity and radiation pattern through interferences of dominating multipole modes excited. In modern nanophotonics, both generation and interference of multipole modes start to play an indispensable role, and they enable nanoscale manipulation of light with many related applications. Here, we review the multipolar interference effects in metallic, metal-dielectric and dielectric nanostructures, and suggest a comprehensive view on many phenomena involving the interferences of electric, magnetic and toroidal multipoles, which drive a number of recently discussed effects in nanophotonics such as unidirectional scattering, effective optical antiferromagnetism, generalized Kerker scattering with controlled angular patterns, generalized Brewster angle, and non-radiating optical anapoles...
March 28, 2017: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
https://www.readbyqxmd.com/read/28220006/chiral-optical-fields-a-unified-formulation-of-helicity-scattered-from-particles-and-dichroism-enhancement
#8
Manuel Nieto-Vesperinas
We establish a general unified formulation which, using the optical theorem of electromagnetic helicity, shows that dichorism is a phenomenon arising in any scattering-or diffraction-process, elastic or not, of chiral electromagnetic fields by objects either chiral or achiral. It is shown how this approach paves the way to overcoming well-known limitations of standard circular dichroism, like its weak signal or the difficulties of using it with magnetodielectric particles. Based on the angular spectrum, representation of optical fields with only right circular or left circular plane waves, we introduce beams with transverse elliptic polarization and possessing a longitudinal component...
March 28, 2017: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
https://www.readbyqxmd.com/read/28219997/phase-resolved-pulse-propagation-through-metallic-photonic-crystal-slabs-plasmonic-slow-light
#9
Anja Schönhardt, Dietmar Nau, Christina Bauer, André Christ, Hedi Gräbeldinger, Harald Giessen
We characterized the electromagnetic field of ultra-short laser pulses after propagation through metallic photonic crystal structures featuring photonic and plasmonic resonances. The complete pulse information, i.e. the envelope and phase of the electromagnetic field, was measured using the technique of cross-correlation frequency resolved optical gating. In good agreement, measurements and scattering matrix simulations show a dispersive behaviour of the spectral phase at the position of the resonances. Asymmetric Fano-type resonances go along with asymmetric phase characteristics...
March 28, 2017: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
https://www.readbyqxmd.com/read/28218381/an-accurate-method-to-quantify-breathing-induced-prostate-motion-for-patients-implanted-with-electromagnetic-transponders
#10
Tommaso Giandini, Costanza M V Panaino, Barbara Avuzzi, Sara Morlino, Sergio Villa, Nice Bedini, Gabriele Carabelli, Sarah C Frasca, Anna Romanyukha, Anatoly Rosenfeld, Emanuele Pignoli, Riccardo Valdagni, Mauro Carrara
PURPOSE: To validate and apply a method for the quantification of breathing-induced prostate motion (BIPM) for patients treated with radiotherapy and implanted with electromagnetic transponders for prostate localization and tracking. METHODS: For the analysis of electromagnetic transponder signal, dedicated software was developed and validated with a programmable breathing simulator phantom. The software was then applied to 1,132 radiotherapy fractions of 30 patients treated in supine position, and to a further 61 fractions of 2 patients treated in prone position...
February 11, 2017: Tumori
https://www.readbyqxmd.com/read/28217826/in-vivo-comparison-of-two-navigation-systems-for-abdominal-percutaneous-needle-intervention
#11
Deqiang Xiao, Yong Li, Huoling Luo, Yanfang Zhang, Xuejun Guo, Huimin Zheng, Qingmao Hu, Fucang Jia
PURPOSE: To compare the accuracy of a Kinect-Optical navigation system with an electromagnetic (EM) navigation system for percutaneous liver needle intervention. MATERIALS AND METHODS: Five beagles with nine artificial tumors were used for validation. The Veran IG4 EM navigation system and a custom-made Kinect-Optical navigation system were used. Needle insertions into each tumor were conducted with these two guidance methods. The target positioning error (TPE) and the time cost of the puncture procedures were evaluated...
February 20, 2017: Abdominal Radiology
https://www.readbyqxmd.com/read/28217716/electromagnetic-confinement-via-spin-orbit-interaction-in-anisotropic-dielectrics
#12
Alessandro Alberucci, Chandroth P Jisha, Lorenzo Marrucci, Gaetano Assanto
We investigate electromagnetic propagation in uniaxial dielectrics with a transversely varying orientation of the optic axis, the latter staying orthogonal everywhere in the propagation direction. In such a geometry, the field experiences no refractive index gradients, yet it acquires a transversely modulated Pancharatnam-Berry phase, that is, a geometric phase originating from a spin-orbit interaction. We show that the periodic evolution of the geometric phase versus propagation gives rise to a longitudinally invariant effective potential...
December 21, 2016: ACS Photonics
https://www.readbyqxmd.com/read/28217410/design-and-analysis-of-a-field-modulated-magnetic-screw-for-artificial-heart
#13
Zhijian Ling, Jinghua Ji, Fangqun Wang, Fangfang Bian
This paper proposes a new electromechanical energy conversion system, called Field Modulated Magnetic Screw (FMMS) as a high force density linear actuator for artificial heart. This device is based on the concept of magnetic screw and linear magnetic gear. The proposed FMMS consists of three parts with the outer and inner carrying the radially magnetized helically permanent-magnet (PM), and the intermediate having a set of helically ferromagnetic pole pieces, which modulate the magnetic fields produced by the PMs...
May 2017: AIP Advances
https://www.readbyqxmd.com/read/28217089/differential-modulation-of-rhythmic-brain-activity-in-healthy-adults-by-a-t-type-calcium-channel-blocker-an-meg-study
#14
Kerry D Walton, Emeline L Maillet, John Garcia, Timothy Cardozo, Isaac Galatzer-Levy, Rodolfo R Llinás
1-octanol is a therapeutic candidate for disorders involving the abnormal activation of the T-type calcium current since it blocks this current specifically. Such disorders include essential tremor and a group of neurological and psychiatric disorders resulting from thalamocortical dysrhythmia (TCD). For example, clinically, the observable phenotype in essential tremor is the tremor itself. The differential diagnostic of TCD is not based only on clinical signs and symptoms. Rather, TCD incorporates an electromagnetic biomarker, the presence of abnormal thalamocortical low frequency brain oscillations...
2017: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/28216677/control-of-terahertz-nonlinear-transmission-with-electrically-gated-graphene-metadevices
#15
Hyun Joo Choi, In Hyung Baek, Bong Joo Kang, Hyeon-Don Kim, Sang Soon Oh, Joachim M Hamm, Andreas Pusch, Jagang Park, Kanghee Lee, Jaehyeon Son, Young U K Jeong, Ortwin Hess, Fabian Rotermund, Bumki Min
Graphene, which is a two-dimensional crystal of carbon atoms arranged in a hexagonal lattice, has attracted a great amount of attention due to its outstanding mechanical, thermal and electronic properties. Moreover, graphene shows an exceptionally strong tunable light-matter interaction that depends on the Fermi level - a function of chemical doping and external gate voltage - and the electromagnetic resonance provided by intentionally engineered structures. In the optical regime, the nonlinearities of graphene originated from the Pauli blocking have already been exploited for mode-locking device applications in ultrafast laser technology, whereas nonlinearities in the terahertz regime, which arise from a reduction in conductivity due to carrier heating, have only recently been confirmed experimentally...
February 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28216590/initial-results-from-squid-sensor-analysis-and-modeling-for-the-elf-vlf-atmospheric-noise
#16
Huan Hao, Huali Wang, Liang Chen, Jun Wu, Longqing Qiu, Liangliang Rong
In this paper, the amplitude probability density (APD) of the wideband extremely low frequency (ELF) and very low frequency (VLF) atmospheric noise is studied. The electromagnetic signals from the atmosphere, referred to herein as atmospheric noise, was recorded by a mobile low-temperature superconducting quantum interference device (SQUID) receiver under magnetically unshielded conditions. In order to eliminate the adverse effect brought by the geomagnetic activities and powerline, the measured field data was preprocessed to suppress the baseline wandering and harmonics by symmetric wavelet transform and least square methods firstly...
February 14, 2017: Sensors
https://www.readbyqxmd.com/read/28216570/an-electromagnetic-sensor-for-the-autonomous-running-of-visually-impaired-and-blind-athletes-part-i-the-fixed-infrastructure
#17
Marco Pieralisi, Valentina Di Mattia, Valerio Petrini, Alfredo De Leo, Giovanni Manfredi, Paola Russo, Lorenzo Scalise, Graziano Cerri
Sport is one of the best ways to promote the social integration of people affected by physical disability, because it helps them to increase their self-esteem by facing difficulties and overcoming their disabilities. Nowadays, a large number of sports can be easily played by visually impaired and blind athletes without any special supports, but, there are some disciplines that require the presence of a sighted guide. In this work, the attention will be focused on marathons, during which athletes with visual disorders have to be linked to the sighted guide by means of a non-stretchable elbow tether, with an evident reduction of their performance and autonomy...
February 14, 2017: Sensors
https://www.readbyqxmd.com/read/28215003/improved-electromagnetic-tracking-for-catheter-path-reconstruction-with-application-in-high-dose-rate-brachytherapy
#18
Elodie Lugez, Hossein Sadjadi, Chandra P Joshi, Selim G Akl, Gabor Fichtinger
PURPOSE: Electromagnetic (EM) catheter tracking has recently been introduced in order to enable prompt and uncomplicated reconstruction of catheter paths in various clinical interventions. However, EM tracking is prone to measurement errors which can compromise the outcome of the procedure. Minimizing catheter tracking errors is therefore paramount to improve the path reconstruction accuracy. METHODS: An extended Kalman filter (EKF) was employed to combine the nonlinear kinematic model of an EM sensor inside the catheter, with both its position and orientation measurements...
February 18, 2017: International Journal of Computer Assisted Radiology and Surgery
https://www.readbyqxmd.com/read/28213724/mobile-phone-use-and-risk-of-brain-tumours-a-systematic-review-of-association-between-study-quality-source-of-funding-and-research-outcomes
#19
Manya Prasad, Prachi Kathuria, Pallavi Nair, Amit Kumar, Kameshwar Prasad
Mobile phones emit electromagnetic radiations that are classified as possibly carcinogenic to humans. Evidence for increased risk for brain tumours accumulated in parallel by epidemiologic investigations remains controversial. This paper aims to investigate whether methodological quality of studies and source of funding can explain the variation in results. PubMed and Cochrane CENTRAL searches were conducted from 1966 to December 2016, which was supplemented with relevant articles identified in the references...
February 17, 2017: Neurological Sciences
https://www.readbyqxmd.com/read/28213224/ordered-titanium-templates-functionalized-by-gold-films-for-biosensing-applications-towards-non-enzymatic-glucose-detection
#20
Katarzyna Grochowska, Mariusz Szkoda, Jakub Karczewski, Gerard Śliwiński, Katarzyna Siuzdak
Recently, metal nanostructures evoke much interest due to application potential in highly sensitive detectors in biochemistry and medical diagnostics. In this work we report on preparation and characteristics of thin (1-100nm) Au films deposited onto highly ordered structured titanium templates for SERS (Surface Enhanced Raman Spectroscopy) and electrochemical sensing. The Ti templates are formed by selective removal of TiO2 nanotubes out of as-anodized titanium substrate. The surface of the obtained material reproduce precisely the bottom layer of the nanotubes and consists of a uniformly distributed dimples with diameter of ~100nm...
May 1, 2017: Talanta
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